EP2199016B1 - Polishing device with rotary joint - Google Patents

Description

The invention relates to a polishing apparatus for zonal polishing of optical lenses with a tiltable base part for the middle or immediate recording of a polishing plate according to the preamble of claim 1 (see, for example DE 10 2004 062 319 ), wherein the base part for the purpose of rotary drive with a rotation axis D having a polishing spindle is connected.

Furthermore, the invention relates to a rotary feedthrough for a polishing spindle for optical surfaces according to the preamble of claim 13 (see, for example DE 199 05 583 ).

The invention also relates to a method for zonal polishing of aspherical, non-rotationally symmetrical lenses using a polishing plate tiltably guided by a polishing spindle according to the preamble of claim 15 (see eg DE 10 2004 062 319 ).

In the production of aspherical or non-rotationally symmetric lenses, such as lenses with a toric surface or free-form surfaces, tools or polishing heads which are smaller than the surface of the lens to be processed, so-called zonal polishing tools, are generally used.

In zonal machining, the tool or the polishing head is guided over the surface, wherein on the areas of the surface to be machined of the lens, which is not covered by the tool, polishing agent is applied, which then between the polishing tool and the surface of the lens to be processed is incorporated, whereby the polishing performance is improved. In order to adapt the polishing head to the shape of the surface to be machined this is tiltably mounted on a ball joint. Furthermore, the polishing head has an elastic carrier layer for the polishing film so that a local deformation of the polishing head to adapt to the shape of the lens is possible.

Such a polishing tool is from the DE 10 2004 062 319 B3 known. It describes a polishing apparatus for optical lenses with a rotation axis X having a receptacle for placement on a polishing machine and arranged on the receptacle cuff for rotatably driving a arranged on the sleeve tool holder or polishing head, wherein the tool holder via a coaxially mounted in the receptacle and in the direction of the axis of rotation X displaceable guide piston is guided tiltably.

As already stated above, the polishing agent is applied to the free parts of the surface to be polished during zonal machining. An additional supply of polishing agent is initially not necessary.

In the processing of spherical surfaces, especially in precision optics, where mineral glass lenses are usually used, large polishing tools are used to obtain a highly accurate spherical surface covering the surface to be polished. The previously described supply of polishing agent is not possible in this case because the surface to be polished is not released during the polishing process. In this case, it is advantageous to supply the polishing agent in other ways.

It is already a device for the supply of polishing agent for the finishing of spherical surfaces of the DE 199 05 583 B4 known. The apparatus comprises a cast forming tool having a spherically shaped working surface for receiving a polishing foil, not shown, with one facing the working surface opening feed channel and with a rotatable, a connecting channel having connecting portion. To the connecting portion in the radial direction, a supply part is connected, which is rotatable relative to the connecting portion, wherein between the connecting portion and the supply part, the leakage for aids granting game is available. The rotary feedthrough with the connecting portion is arranged according to embodiment Fig. 1 between the spindle and a connection flange for the tool. According to embodiment Fig. 3, the rotary feedthrough with the connecting portion is part of the interchangeable tool, which is fastened to the spindle via the connecting flange. A simple replacement of the rotary feedthrough or the polishing tool is not possible.

The relative angular position between the tool with the working surface and the surface to be machined is rigid. A pivoting of the tool or the base part is not possible.

The known from the prior art polishing tool is not designed as a polishing plate, but a rigid casting with an applied polishing film. A polishing plate according to this invention is characterized by a support member, usually made of plastic, on which an elastic foam layer is applied. The foam layer serves as a carrier layer for a preferably interchangeable polishing film, which is also referred to as a polishing pad.

The elastic foam layer is necessary so that an adjustment of the polishing film to the local conditions of the surface to be polished on the tilting movement of the polishing plate on the ball joint addition is possible. As already stated, as a rule aspherical surfaces are polished whose curvature varies both in the radial direction and in the circumferential direction.

The invention has for its object to provide means for a polishing device for the zonal machining of non-rotationally symmetric surfaces, which ensure an improved supply of polishing agent.

The object is achieved according to the invention by the features of claims 1, 13 and 15.

The use of a rotary union for supplying polishing agent, which is arranged with respect to the rotation axis D and with respect to the base part opposite to the polishing spindle, allows the supplementary supply of polishing agent between a polishing head and a surface to be processed in spite of the use of a pivotable base part. The rotary feedthrough and the polishing spindle or the ball joint are thus arranged with respect to the rotation axis D adjacent to the base part, so that the base part is placed with respect to the rotation axis D between the polishing spindle or the ball joint and the rotary feedthrough.

The polishing spindle generally has a ball joint, via which the base part is tiltably mounted on the polishing spindle. With the use of the rotary feedthrough at the position according to the invention, the distance between the ball joint and a aufzusetzenden polishing head increases, which initially adversely affects the polishing behavior. However, a passage of polishing agent in the region of the ball joint or even in the spindle is avoided.

The use of a coupling element by means of which the rotary feedthrough on the base part on the polishing spindle is detachably plugged or clipped, ensures a simple or even mechanical change of the rotary feedthrough for the purpose of cleaning or watering the same. Such an exchange is not possible with the rotary feedthrough known from the prior art because it must be rigidly bolted to the spindle and the polishing tool.

It can also be advantageous for this purpose if the rotary feedthrough has at least one polishing medium channel system with at least one feed opening and with at least one outlet opening, wherein the outlet opening of the polishing medium channel system is arranged opposite to the polishing spindle with respect to the base part. It would also be possible to spatially separate the rotary union and the duct system or a hose connection for passing polishing agent. Ultimately, it is important that the polishing agent emerges with respect to the direction of the axis of rotation in front of the ball joint or in front of the base part where it is fed to a polishing plate to be arranged. The preposition "before" refers to the free side of the base part, on which the polishing plate and the rotary union are arranged.

Furthermore, it may be advantageous if the feed opening of the polishing medium channel system is designed as an annular channel and has a plurality of mutually separate connection channels, wherein the respective connecting channel connects the annular channel with the outlet opening. The rotary feedthrough known from the prior art also has a polishing medium channel system with different connecting channels. However, these connecting channels, so far as they are separated from each other, do not fulfill the abovementioned feature because they do not connect the annular channel to the outlet opening, but rather lead from the annular channel into a common central channel which ultimately directs the polishing agent to the outlet opening. The use of completely separate Connecting channels ensures some redundancy in case of blockage of one of the channels.

It can also be advantageous if the respective connecting channel has a direction component Vd parallel to the axis of rotation D, the respective connecting channel being arranged at least a part of its length at a distance c from the axis of rotation D. Such a design of the respective connecting channel ensures the supply of polishing agent in front of the ball joint or in front of the base part, on the one hand, and the avoidance of an unnecessarily large distance between the polishing plate holder and the ball joint on the other. Each of the connecting channels thus has both a radial and an axial direction component Vd, Vr, so that the overall result is a funnel-shaped polishing agent channel system.

It may advantageously be provided that the rotary union for the purpose of washing or cleaning is removably attached to the base part. During the ongoing operation, so in continuous tracking or continuous circulation of polishing agent curing of the same is not possible. In the case of standstill of the device, that is, without continuous polishing circulation, however, drying out or a hardening of the polishing agent associated therewith is unavoidable. With a removable rotary feedthrough, the handling of a polishing device formed in this way can be substantially simplified. Removable means in this sense that the rotary feedthrough by simple locking means and / or clamping means with a few simple steps or even mechanically removed and can also be mounted accordingly.

Of particular importance for the present invention, when the rotary feedthrough with respect to the direction of the rotation axis D has a front end edge and the ball joint has a center M, wherein between the end edge and the center M with respect to the direction of the rotation axis D provided a distance b is, wherein the distance b is a maximum of 25 mm or between 5 mm and 20 mm or 11 mm. As already mentioned, it is important that the receptacle for a polishing plate is no further than absolutely necessary from the center of the ball joint. If the rotary feedthrough forms the receptacle for the polishing head, then the distance b described above should not be exceeded. As the distance b increases, setting torques occur during the machining, which adversely affect a dynamic adaptation of the base part with the polishing plate arranged thereon to the geometry or inclination of the part surface to be machined.

When mounted polishing plate, the rotary feedthrough between the base and the polishing plate is arranged. In the application, so with attached polishing plate, the rotary union thus placed ensures optimal supply of polishing agents on or in the polishing plate for the purpose of continuing through this in the area between a polishing film and the surface to be machined.

The outlet opening of the polishing agent channel system is arranged between the base part and the polishing plate. The outlet opening is located between the ball joint and the polishing plate, since the ball joint is arranged centrally and the Polishing agent should preferably be introduced centrally into the polishing plate. Starting from the centric initiation, a distribution of the polishing agent in the radial direction is ensured due to the rotation of the polishing plate during operation.

In addition, it may be advantageous if the polishing plate has a polishing pad and between the center M of the ball joint and the polishing pad with respect to the direction of the rotation axis D, a distance a is provided, wherein the distance a a maximum of 40 mm or between 10 mm and 30 mm or 25 mm. The polishing plate is usually formed from a carrier, a support arranged on the flexible or elastic carrier layer and arranged on the carrier layer polishing pad. Depending on the thickness of the carrier layer, the distance a varies between the center M of the ball joint and the polishing pad. As explained above, too great a distance has a negative influence on the dynamic tiltability of the polishing plate or the adaptability of the polishing plate to the angular position of the surface to be polished in the case of the dynamic processing thereof.

Furthermore, it may be advantageous if the rotary feedthrough is designed as a coupling part for the polishing plate or has at least one coupling element for the polishing plate. The polishing plate is preferably attached or clipped, so that it is mechanically changeable. For the purpose of axial attachment of the polishing plate a clip connection is sufficient, because the polishing plate is pressed during processing by the base part or the spindle against the surface to be machined. Rather, it requires in the polishing plate of sufficient form or force fit in the circumferential direction and in the radial direction, so that the polishing movement or the polishing forces can be transmitted. In the case of positive connection this driving lugs are provided in this rule, take into account the above conditions. The coupling of the polishing plate regarding basically can be provided a function separation.

It may be advantageous if the rotary feedthrough is integrally connected to the base part. This would make the design of the base part or the rotary feedthrough somewhat simpler, but the disassembly would be somewhat more difficult for the purpose of cleaning or washing the rotary feedthrough.

Finally, it may be advantageous if the polishing spindle has an axial translation axis T and a further rotary leadthrough for gas. For the purpose of adapting the base part or the polishing plate attached thereto to the height differences of the surface to be machined, a pneumatic pretensioning of the base part via the ball joint is generally provided, which is supplied via the further rotary union with corresponding gas pressure.

The provision of a coupling part, by means of which the rotary feedthrough on the base part of the polishing spindle is detachably attachable or clipped, makes the change for the purpose of cleaning and / or replacement very easy. In addition, the axial securing of the rotary feedthrough on the one hand as well as the power transmission to the rotary and translational drive by the spindle or the base part by means of positive and / or frictional connection on the other hand should be ensured.

For this purpose, it may be advantageous if at least one coupling element is provided for the detachable plugging or clipping of a polishing plate. Since the rotary feedthrough according to the invention can be placed on the base part or plugged or clipped, it is advantageous to attach the polishing plate via a corresponding coupling element to the rotary feedthrough. This attachment is usually designed as Klips- or plug connection, so that it can be solved as already mentioned with a few simple steps or even by machine to replace the polishing plate as needed. The replacement can be done without dismantling other spindle parts. Any securing means to be provided should be able to be released or fixed in a few steps.

The introduction of polishing agent between the polishing plate and the lens during polishing via a rotary leadthrough disposed between the polishing spindle and the polishing plate improves the polishing performance to be achieved and the polishing quality. The polishing agent applied laterally to the polishing plate and incorporated in the polishing process may in most cases be sufficient.

Further advantages and details of the invention are explained in the patent claims and in the description and shown in the figure.

An illustrated polishing device 1 consists of a spindle 1.2, at the front end of a base member 1.1 is provided which carries a rotary feedthrough 3 frontally. On the rotary feedthrough 3, a polishing plate 2 is placed or placed as shown.

The polishing spindle 1.2 has a housing 1.7, which with a drive, not shown for the purpose of rotary Drive is connected. Within the housing 1.7, an axially movable piston 1.5 is mounted, at the end face end of a ball joint 1.3 is provided for tiltably receiving the base part 1.1. The piston 1.5 is axially movable in the direction of a translational axis T and is acted upon by a cylinder 1.8, which is connected to a further rotary union 1.4 for gas, with axial force. The rotational movement is transmitted via the housing 1.7 to a bellows 1.6, which in turn is connected to the base part 1.1 for the purpose of rotary drive. In order to ensure a defined position between the base part 1.1 and the piston 1.5 and the housing 1.7, the housing 1.7 at the front end of a stop and centering 1.9, against which the base part 1.1 in the axial direction and / or radial direction can be applied. The axial contact is made by a corresponding movement of the piston 1.5 as shown below, so that the base member 1.1 abuts against the stop means 1.9 with simultaneous compression of the bellows 1.6.

The rotary feedthrough 3 is essentially formed from a housing 3, which is placed on the front side of the base part 1.1 and secured by a securing means 3.9. The housing 3 rotates with the base part 1.1. In order to ensure the rotary feedthrough 3, a wall part 3.5 is provided, which is mounted in a corresponding recess on the housing 3 and movable in the circumferential direction. The wall part 3.5 has a U-shaped cross-section and thus forms a channel wall 3.5 of an annular channel 3.2 of the rotary feedthrough 3. The wall part 3.5 does not complete the rotational movement of the housing 3 and has a feed 4 for polishing on. Within the housing 3, a first connecting channel 3.4 and a second connecting channel 3.4 'are provided. The respective connection channel 3.4, 3.4 'extends from the annular channel 3.2 to a front end or an outlet opening 3.3 of the housing 3. The annular channel 3.2 in this case forms a feed opening 3.2 for polishing. The respective connecting channel 3.4, 3.4 'has with reference to a rotation axis D of the polishing spindle 1.2 both a radial direction component Vr and an axial direction component Vd. The aforementioned directional components Vr, Vd are described using the example of the frontal section of the respective connecting channel 3.4, 3.4 '. However, the respective connecting channel 3.4, 3.4 'has, in addition to the end-side channel section, also an immediately adjoining, annular channel-side channel section, which likewise has both a radial direction component Vr and an axial direction component Vd. Overall, there is an inlet geometry of the polishing medium channel system 3.1 with a radial and an axial flow component, whereby a short design is favored.

The rotary feedthrough 3 is coupled via a coupling part 3.8 to the base part 1.1.

The rotary feedthrough 3 has various coupling elements 3.7, which are formed as annular beads and which serve for plugging or clipping of the polishing plate 2. The polishing plate 2 has a corresponding carrier 2.1, which is due to its geometry on the aforementioned coupling elements 3.7 placed or plugged. On the support 2.1, a carrier layer 2.2 formed from foam is arranged, on the end face, finally, a polishing pad 2.3 is attached.

Coaxially to the axis of rotation D, both the polishing pad 2.3 and the carrier layer 2.2 and the carrier 2.1 have a recess through which the emerging from the outlet opening 3.3 polishing agent can escape against a surface to be polished.

The ball joint 1.3 has a center M, which has a distance a to the polishing pad 2.3 with respect to the direction of the axis of rotation D. Between the center M and a front edge 3.6 of the rotary feedthrough 3, a distance b is provided. The difference between the distance a and the distance b results essentially from a height, not shown, of the carrier layer 2.2 of the polishing plate 2.

LIST OF REFERENCE NUMBERS

1

polisher

1.1

base

1.2

polishing spindle

1.3

ball joint

1.4

further rotary feedthrough

1.5

piston

1.6

bellow

1.7

casing

1.8

cylinder

1.9

Stop and centering device

2

polishing plate

2.1

carrier

2.2

Carrier layer, foam part

2.3

polishing pad

3

Rotary feedthrough, housing

3.1

Polish channel system

3.2

Feed opening, annular channel

3.3

outlet opening

3.4

connecting channel

3.4 '

connecting channel

3.5

Wall part, duct wall

3.6

front edge

3.7

coupling member

3.8

coupling part

3.9

securing means

4

supply pipe

M

Focus

a

distance

b

distance

c

distance

D

axis of rotation

T

translation axis

V

vector

vd

directional component

Vr

directional component

Claims (15)

1. A polishing device (1) for the zonal polishing of aspherical, non-rotationally-symmetrical optical lenses, comprising a tiltable base part (1.1) for indirectly holding a polishing plate (2), wherein the base part (1.1) is connected, for rotational drive purposes, to a polishing spindle (1.2) having an axis of rotation D, characterized in that a rotary feed-through (3) is provided on the base part (1.1) for the purpose of supplying polishing agent, wherein the rotary feed-through (3) is arranged opposite the polishing spindle (1.2) relative to the direction of the axis of rotation D and relative to the base part (1.1).
2. The device according to claim 1, characterized in that the rotary feed-through (3) has at least one polishing agent channel system (3.1) having at least one supply opening (3.2) and having at least one outlet opening (3.3), wherein the outlet opening (3.3) of the polishing agent channel system (3.1) is arranged opposite the polishing spindle (1.2) relative to the base part (1.1).
3. The device according to claim 2, characterized in that the supply opening of the polishing agent channel system (3.1) is designed as an annular channel (3.2) and comprises a plurality of separate connection channels (3.4, 3.4'), wherein the respective connection channel (3.4, 3.4') connects the annular channel (3.2) to the outlet opening (3.3).
4. The device according to claim 3, characterized in that the respective connection channel (3.4, 3.4') has a direction component Vd parallel to the axis of rotation D, wherein the respective connection channel (3.4, 3.4') is arranged at a distance c to the axis of rotation D, at least over part of its length.
5. The device according to any of the preceding claims, characterized in that the rotary feed-through (3) is fastened to the base part (1.1) in such a way as to be removable for washing or cleaning purposes.
6. The device according to any of the preceding claims, characterized in that the rotary feed-through (3) has a front edge (3.6) relative to the direction of the axis of rotation D, and in that a ball-and-socket joint (1.3) is provided which has a centre point M, wherein a distance b is provided between the front edge (3.6) and the centre point M in relation to the direction of the axis of rotation D, wherein the distance b is at most 25 mm or is between 5 mm and 20 mm or is 11 mm.
7. The device according to any of the preceding claims, characterized in that a polishing plate (2) is installed, wherein the rotary feed-through (3) between the base part (1.1) and the polishing plate (2) is arranged directly on the base part (1.1).
8. The device according to any of claims 2 to 7, characterized in that a polishing plate (2) is provided and the outlet opening (3.3) of the polishing agent channel system (3.1) is arranged between the base part (1.1) and the polishing plate (2).
9. The device according to any of claims 6 to 8, characterized in that a polishing plate (2) is provided and the polishing plate (2) has a polishing pad (2.3) and a distance a is provided between the centre point M of the ball-and-socket joint (1.3) and the polishing pad (2.3) relative to the direction of the axis of rotation D, wherein the distance a is at most 40 mm or is between 10 mm and 30 mm or is 25 mm.
10. The device according to any of the preceding claims, characterized in that the rotary feed-through (3) is designed as a coupling part for the polishing plate (2) or has at least one coupling element (3.7) for the polishing plate (2).
11. The device according to any of claims 1 to 4 or 6 to 10, characterized in that the rotary feed-through (3) is connected in one piece with the base part (1.1).
12. The device according to any of the preceding claims, characterized in that the polishing spindle (1.2) has an axial translation axis T for the translational movement of the base part (1.1) and has a further rotary feed-through (1.4) for gas.
13. A rotary feed-through (3) for a polishing spindle (1.2) for optical surfaces for supplying polishing agent to a polishing tool (2) that can be attached to the rotary feed-through (3), characterized in that the polishing tool is a polishing plate, in that a coupling part (3.8) is provided for the purpose of coupling to a polishing spindle (1.2) for the zonal polishing of aspherical, non-rotationally-symmetrical optical lenses, by means of which coupling part the rotary feed-through (3) can be clipped onto a tiltable base part (1.1) on the polishing spindle (1.2).
14. The rotary feed-through (3) according to claim 13, characterized in that at least one coupling element (3.7) is provided for the detachable plugging-on or clipping-on of a polishing plate (2).
15. A method for the zonal polishing of aspherical, non-rotationally-symmetrical lenses using a polishing plate (2) which is guided in a tiltable manner by a polishing spindle (1.2), wherein a tiltable base part (1.1) for indirectly holding a polishing plate (2) is provided on the polishing spindle (1.2), characterized in that, during the polishing operation, polishing agent is introduced between the polishing plate (2) and the lens via a rotary feed-through (3) that is arranged between the polishing spindle (1.2) and the polishing plate (2), wherein the rotary feed-through (3) is held on the polishing spindle (1.2) by the base part (1.1).

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